[Mlir-commits] [mlir] [mlir][reducer] Separate Reduction Steps in `findOptimal` and `applyPatterns` (PR #190560)

[llvmlistbot at llvm.org]

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@@ -101,17 +48,20 @@ static LogicalResult findOptimal(ModuleOp module, Region &region,
   // Duplicate the module for root node and locate the region in the copy.
   if (failed(root->initialize(module, region)))
     llvm_unreachable("unexpected initialization failure");
-  root->update(initStatus);
+
+  // Create a duplicate of the root node as the first variant of the root.
+  // This will keep the root intact when applying `applyFn`.
+  ReductionNode *firstVariant = allocator.Allocate();
+  new (firstVariant) ReductionNode(root, ranges, allocator);
+  root->addVariant(firstVariant);
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aidint wrote:

I explained here:
https://github.com/llvm/llvm-project/pull/190560#issuecomment-4210319799

https://github.com/llvm/llvm-project/pull/190560